The present invention relates to an arrangement for regulating a cooling air flow in a motor vehicle, and particularly to a vent system for diverting a cooling air flow toward the atmosphere from its normal path past a blower and through the vehicle.
On the basis of German Published Unexamined Patent Application DE-OS No. 27 40 918, an internal-combustion engine is known having a soundproof capsule and a water cooler arranged outside said capsule. A blower is arranged in an air guiding space connecting the water cooler and the capsule. Between the blower and the capsule, an air outlet opening is arranged in the air guiding space in the area of the bottom side of the vehicle. One disadvantage of this arrangement is that the blower drive during the operation of the internal-combustion engine must also be switched on during high vehicle speed because the blower is assigned directly to the water cooler and the air outlet opening is arranged in the area between the blower and the capsule. This arrangement results in an unfavorable dynamic pressure at high driving speed which is not adequate for letting a sufficient cooling air flow pass through the water cooler without the support of the blower.
Also, on the basis of German Published Unexamined Patent Application DE-OS No. 25 40 733, an axial flow blower is known that is arranged in an air guiding space. Guide blades are arranged in front of and behind the moving blades. In this case, it is a disadvantage that the guide blades are arranged rigidly and thus are arranged optimally only for a previously determined blower delivery flow.
In addition, a cooling system is known from US-PS 23 51 203 having guide blades that must be adjusted by means of an adjusting drive as a function of a parameter of the internal-combustion engine, such as the cooling water temperature.
A cooling system is known from German Published Unexamined Patent Application DE-OS No. 22 16 585 that has a heat exchanger at which an air guiding housing is fastened surrounding an axial flow blower. In the air guiding housing, a cooling air outlet opening is provided that can be closed by a closing part, the closing or opening taking place as a function of the operating condition of the vehicle.
One object of the present invention is to improve the efficiency of a blower by simple means and by these means also minimize or otherwise prevent the emergence of sounds from a ventilated capsule.
According to the present invention, a cooling air system is provided for regulating a flow of air passing through a heat exchanger mounted in a cooling system housing and discharging into an internal-combustion engine housing. The cooling system housing is formed to include an opening to the atmosphere. The improvement of the present invention includes air guiding means for conducting the flow of air from the heat exchanger to the internal-combustion engine housing along a path through the cooling system housing. The air guiding means is formed to include an outlet in communication with the atmosphere opening.
The improvement also includes a vent movable between an outlet-opening and an outlet-closing position, and guide blade means for regulating the flow of air through the air guiding means. Control means is provided for moving selectively the vent to its outlet-opening position to discharge a portion of the air flow toward the atmosphere opening via the outlet opening. The guide blade means can include at least one pivotable guide blade and the control means can be responsive to a predetermined orientation of said pivotable guide blade.
Preferred embodiments of the present invention have the advantage that, in the case of a slow flow velocity of the cooling air flow, a blower can be switched on and pivotable guide blades, which are arranged in front of and behind the moving blades of the blower, can be positioned with an adjusting drive system, in such a way that the blower operates at optimized efficiency at any flow velocity of the cooling air flow. In the case of a higher flow velocity of the cooling air flow, which occurs at a higher motor vehicle speed, the blower is switched off and the guide blades are swivelled so that no sounds can be emitted from the ventilated capsule against the flow direction from the cooling arrangement. The cooling air outlet opening is opened and the cooling air flow is carried off in the direction of the bottom side of the vehicle into a vacuum area to ensure cooling of the internal-combustion engine in the case of a dynamic pressure caused by the flow-in velocity of the cooling air.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawing which shows, for purpose of illustration only, a preferred embodiment in accordance with the present invention.